Two fabrics and a destination

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Lately everything seems to revolve around the virus of fashion. Here in Spain at the beginning and perhaps now it was missing masks. I don’t know if this is a solution but ….. to the bull.

Because N95 and surgical masks are scarce and should be reserved for health care workers, many people are making their own coverings. Now, researchers report in ACS Nano that a combination of cotton with natural silk or chiffon can effectively filter out aerosol particles — if the fit is good.

SARS-CoV-2, the new coronavirus that causes COVID-19, is thought to spread mainly through respiratory droplets when an infected person coughs, sneezes, speaks or breathes. These droplets form in a wide range of sizes, but the tiniest ones, called aerosols, can easily slip through the openings between certain cloth fibers, leading some people to question whether cloth masks can actually help prevent disease.The researchers used an aerosol mixing chamber to produce particles ranging from 10 nm to 6 μm in diameter. A fan blew the aerosol across various cloth samples at an airflow rate corresponding to a person’s respiration at rest, and the team measured the number and size of particles in air before and after passing through the fabric.

One layer of a tightly woven cotton sheet combined with two layers of polyester-spandex chiffon — a sheer fabric often used in evening gowns — filtered out the most aerosol particles (80-99%, depending on particle size), with performance close to that of an N95 mask material.

However, a 1% gap reduced the filtering efficiency of all masks by half or more, emphasizing the importance of a properly fitted mask.